Synthesis
General procedure for the synthesis of 3-chloro-N-methoxy-N-methylaniline from 3-chlorobenzyl alcohol and dimethylhydroxylamine hydrochloride: in a pre-oven-dried 15 mL glass vial fitted with a magnetic stir bar, Cu(OAc)2-H2O (12 mg, 6 mol%), N,O-dimethylhydroxylamine hydrochloride (117 mg, 1.2 mmol), 3- chlorobenzyl alcohol (1 mmol), 70% TBHP aqueous solution (0.17 mL, 1.2 mmol), CaCO3 (120 mg, 1.2 mmol), and MeCN (1 mL). Subsequently, the glass vials were rinsed three times with nitrogen and the reaction mixture was stirred at room temperature for 1 hour. Next, the reaction mixture was continued to be stirred at 80 °C for 24 hours. After completion of the reaction, the mixture was cooled to room temperature. All volatiles were removed under vacuum. The product was extracted with EtOAc (20 mL) and the organic layer was washed with saturated aqueous NaHCO3 solution. Subsequently, the organic layer was dried with Na2SO4 and the solvent was removed under vacuum. Finally, the Weinreb amide product was purified by silica gel column chromatography (100-200 mesh) using a gradient elution of petroleum ether (boiling point 60-80 °C) and EtOAc. All amide products were identified by GC-MS, 1H NMR and 13C NMR spectral analysis.
References
[1] Synthesis (Germany), 2015, vol. 47, # 4, p. 526 - 532
